(CBS News) On the heels of last week's presidential debate, Mitt Romney has emerged with a one-point edge over President Obama in Colorado and has cut the president's lead in half in Wisconsin, according to a new Quinnipiac University/CBS News/New York Times poll.

In Wisconsin, where Mr. Obama led Romney by six percent last month, the president now holds just a three-point advantage, with 50 percent to Romney's 47 percent support. Last month, the president led Romney 51 to 45 percent.

In Colorado, the two remain locked in a dead heat, with Romney leading Mr. Obama 48 percent to 47 percent, within the poll's margin of error. Last month, also within that margin, Mr. Obama had the one-point edge, with 48 percent to Romney's 47 percent.

In Virginia, the presidential race remains essentially unchanged, with Mr. Obama holding on to a small lead over Romney, with 51 percent support to Romney's 46. In September, the president led Romney 50 percent to 46 percent there.

All three polls, conducted from October 4-9, began surveying voters after the first presidential debate.

By about four to one, voters in all three of these battleground states say Romney won last week's presidential debate, and sizable numbers say the debate made them think better of him. But majorities say the debate did not affect their vote.

In Colorado, only 16 percent of likely voters said Mr. Obama won the debate, while 72 percent chose Romney. In Virginia, the breakdown was similar, with 70 percent choosing Romney and 17 percent selecting the president. In Wisconsin, 65 percent said Romney won and 17 percent said Mr. Obama did.

The debate had a positive impact on voters' impressions of Romney. More than four in ten voters in these states who watched the first presidential debate (and 51 percent in Colorado) say it made them feel better about Romney. Fewer than one in 10 said that about Mr. Obama; more say it made them think worse of him.

Among voters who say the debate will impact their vote, the advantage goes to Romney. Even though majorities in these battlegrounds say the debate will have no effect on their vote, twice as many voters said the debate would make them more likely to vote for Romney than said so of Mr. Obama. Among independent voters, about half in these battleground states say the debate gave them a better impression of Romney, and about a quarter in each state say it made them more likely to vote for him.

Romney made gains among voters who are paying a lot of attention to the presidential campaign. Among these voters, Romney leads in Colorado by 53 percent to 44 percent, and in Wisconsin he leads by a smaller margin (51 percent to 47 percent). When measuring voters who have been paying close attention, the race becomes even in Virginia, 49 percent to 49 percent.

Republicans continue to be more enthusiastic than Democrats about voting this year in general. More than half of Republicans in Colorado and Wisconsin are more enthusiastic about voting in this election; this is true of just over a third of Democrats. In Virginia, the enthusiasm gap is narrower, with 48 percent of Republicans and 40 percent of Democrats identifying as more enthusiastic about voting this year.

Heading into tonight's vice presidential debate, voters in these three battleground states expect Paul Ryan to emerge the victor over Vice President Joe Biden. In Colorado, 47 percent of voters picked Ryan as the likely winner, while 30 percent picked Biden and 22 percent said they didn't know. In Wisconsin, Ryan bested Biden 49 percent to 32 percent. In Virginia, the gap was more narrow: 36 percent said Biden would likely win the debate, 41 percent chose Ryan, and 21 percent said they didn't know.

Most Republicans and Democrats think their own party's vice presidential candidate will win the debate, though Republicans are more confident than Democrats. More independents are predicting a Ryan victory.

Joe Biden has a net favorable rating in Virginia, but he is viewed more unfavorably in Colorado and Wisconsin. Paul Ryan is viewed more favorably than unfavorably by voters in all three states, though more than one in four voters Colorado and Virginia said they don't know enough about him yet.

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